1. Field of the Invention
The present invention relates to a headset used for a mobile communication terminal and, more particularly, to a compact and portable antenna mounted inside a communication headset.
2. Description of the Background Art
In general, a radio earphone-microphone for a mobile communication terminal, or the like, is connected to the terminal by way of a wire. Korea Patent Application No. 2000-38718, dated Jul. 6, 2000, discloses a conventional radio earphone-microphone that includes a parent device connected to a mobile communication terminal and a child device wirelessly connected to the parent device. A transmission antenna and a reception antenna are installed inside a support bar in the child device.
The transmission and the reception antenna are installed close to the inside of the support bar. The transmission power flows from the transmission antenna to the reception antenna, resulting in performance degradation of the overall system due to interference between the transmission antenna and the reception antenna.
Distortion and performance degradation also occur when a microphone is installed at an end portion of the antenna, because a voice signal generated by the microphone is transmitted as a module by using an electric wire passing around the antenna. This results in reception being deteriorated due to a back current of the signal and interference. Furthermore, due to an impedance change, the antenna may not function properly.
FIG. 1 is a perspective view of a chip design with the antenna installed on a radio frequency (RF) module. Antenna 104 is mounted as an integrated circuit on a printed circuit board (PCB) 102 of a module of a mobile communication terminal. That is, in this structure, a dipole or a helical antenna is mounted on the surface of the PCB 102 by using a dielectric substance having a high dielectric constant. The dielectric constant of the dielectric substance is very high to provide for a very short wavelength and thus, a compact terminal. Due to the high dielectric constant, a power loss takes place. Also, the transmission characteristics and the gain of the antenna can be degraded.
FIG. 2 is a perspective view of a print-type monopole antenna installed on a PCB module of a mobile communication terminal. A monopole antenna 108 printed on the module PCB 106 is inexpensive. However, since a certain distance should be maintained from a ground plane, and since the dielectric constant of the substrate is small, module integration is difficult. Moreover, if the antenna is positioned close to the RF module, it would be susceptible to noise generated from the module. As such, the transmission properties of the antenna are degraded.